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Finding the Fourth Proportional to 999.12, 1,378.86 and 557.13

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Solution

The fourth proportional to 999.12, 1,378.86 and 557.13 is: 768.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.12 : 1,378.86 = 557.13 : x
  2. Step 2: Convert to fraction form
    999.12/1,378.86 = 557.13/x
  3. Step 3: Cross multiply
    999.12x = 1,378.86 × 557.13
  4. Step 4: Simplify right side
    999.12x = 768,204.27
  5. Step 5: Solve for x
    x = 768,204.27/999.12
  6. Step 6: Final answer
    x = 768.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.